The invention relates to a delivery unit having a delivery pump for delivering fuel from a fuel tank to an internal combustion engine of a motor vehicle, having a flange which is to be fixed in an opening of the fuel tank and having a support for securing the delivery pump and/or a surge chamber in a designated position in the fuel tank.
Delivery units of this type are frequently used in motor vehicles today and are known in practice. The support of the known delivery unit is of telescopic design and has a spring for prestressing a constructional unit comprising the delivery pump and surge chamber toward the bottom of the fuel tank. The flange closes the opening in the fuel tank.
A disadvantage of the known delivery unit is that in the case of today""s generally very flat fuel tanks the delivery pump and the surge chamber are of very wide design and therefore requires a very wide opening. However, a large opening in the fuel tank inevitably leads to a large sealing region between the flange and the fuel tank and therefore to a large escape of fuel vapors from the fuel tank.
The invention is based on the problem of designing a delivery unit of the type mentioned at the beginning in such a manner that it requires a particularly small opening in the fuel tank and can be fitted in as simple a manner as possible.
According to the invention, this problem is solved by at least one pivotable means of securing the surge chamber and/or the delivery pump with respect to the flange when the delivery unit is separated from the fuel tank.
This design enables the delivery pump or the surge chamber to be pivoted into a space-saving position and introduced into the fuel tank. The surge chamber, which is of a low size, can also be of elongated design. The delivery unit according to the invention can thereby be fitted through particularly small openings and in very flat fuel tanks. The support holds the delivery unit and/or the surge chamber in the designated position when fitted into the fuel tank. The delivery unit according to the invention can therefore be fitted in a particularly simple manner.
The support could have, for example, a flexible shaft or a spring element for the pivotable means of securing the delivery pump or the surge chamber. The delivery unit according to the invention is designed in a particularly simple manner structurally and has great stability if the support has a pivot bearing. The pivot bearing can either have a bearing spindle for pivoting the delivery pump or the surge chamber in one direction or a spherical head for pivotability in two directions.
According to another advantageous development of the invention, the means of securing the delivery pump and/or the surge chamber in the designated position in the fuel tank requires a particularly low constructional outlay if the pivot bearing has means for locking it in a designated position.
The surge chamber or the delivery pump is frequently not arranged precisely below the opening of the fuel tank. According to another advantageous development of the invention, a bending moment acting on the flange can be reliably avoided if the support is designed to prestress the pivot bearing in the direction of the bottom of the fuel tank. This design leads to a particularly low stress on the connection of the flange to the fuel tank. This further reduces an escape of fuel vapors out of the fuel tank.
Tilting of the surge chamber or the delivery unit within the fuel tank can be avoided in a simple manner if on its region lying opposite the pivot bearing the support has a supporting arm which is provided for supporting it on the bottom of the fuel tank. By means of this design, it can also be ensured that only perpendicular forces are introduced into the flange.
The delivery unit according to the invention is reliably held in its designated position if the support engages laterally around the surge chamber or the delivery pump.
The bottom of the fuel tank frequently has tolerances which, in the case of the known delivery unit, lead to an uneven arrangement of the delivery unit or the surge chamber. However, according to another advantageous development of the invention, the delivery unit and/or the surge chamber bear in a particularly smooth manner against the bottom of the fuel tank if a connection of the support to the surge chamber or to the delivery unit has a mounting means.
The structural simplification of the delivery unit according to the invention is assisted further if the support has a first supporting part which is fixed vertically to the flange and a second supporting part having the supporting arm, and if the pivot bearing is arranged between the two supporting parts.
After installation in the fuel tank the delivery unit according to the invention is held in its designated position in a particularly reliable manner if the first supporting part has a guide for a locking part penetrating into a recess of the second supporting part.
According to another advantageous development of the invention, the means for locking the supporting parts in their designated position are designed in a particularly simple manner structurally if the guide of the first supporting part and the recess of the second supporting part are each designed as holes in alignment with each other and the locking part is designed as a rod.
In a further advantageous refinement, the surge chamber is effectively prevented from twisting with respect to the flange by two supports being arranged instead of one support. The arrangement of the supports on both sides of the surge chamber has proven advantageous. Otherwise, these supports have the same designs as the device according to the invention having one support.